To relax a red-eye effect in photography using an electronic flash (flash), a technique is conventionally used, in which human pupils are pre-illuminated with flash light before photography, thereby contracting the pupils (e.g., Japanese Patent Publication No. 58-48088). This technique should suppress the amount of flash light reflected by retinas by contracting the pupils before photography.
In another technique used in a digital still camera, image data by flash photography and that by non-flash photography are compared. With this processing, the portions and sizes of red eyes generated by reflection of flash light on the retinal positions of eyes are detected from the image data by flash photography, and the image data is corrected (e.g., Japanese Patent No. 3114103).
In Japanese Patent Publication No. 58-48088 using the conventional red-eye relaxation means, photography is permitted after the predetermined light emission by the red-eye relaxation means assuming that the red-eye relaxation effect is obtained. However, whether the red-eye relaxation effect is obtained can be known only after photography.
In Japanese Patent No. 3114103, image data by flash photography and that by non-flash photography are compared to detect the positions and sizes of red eyes generated by reflection of flash light on the retinal portions of eyes from the image data by flash photography. However, the photographic conditions of the two image data do not coincide (one image data is obtained by non-flash photography, and the other is obtained by flash photography). In addition, at the time of flash photography, since the illuminance is too low, the pupils are dilated. At this time, an image 111 shown in FIG. 8 is obtained. At the time of non-flash photography, since the illuminance is sufficient, the pupils are contracted. At this time, an image 113 shown in FIG. 8 is obtained. The target of red-eye correction is the image 111 at the time of flash photography, i.e., the image with the dilated pupil. For this reason, the correction result tends to be unnatural because the region to be corrected is large.
Furthermore, in the image obtained by non-flash photography, the positions or sizes of red eyes cannot accurately be detected because the brightness is too low.